Pope Pelagius I served as the head of the Roman Catholic Church from 556 to 561 AD. He was known for his efforts to strengthen the Church's authority and promote Christian teachings during a time of political instability in the Roman Empire. His papacy focused on addressing various theological disputes and maintaining unity among Christians. During his tenure, Pelagius I also worked to improve relations with the Byzantine Empire, which was crucial for the Church's influence in the region. He is remembered for his commitment to the faith and his role in the early development of the papacy as a significant religious institution.